There are no regulations or necessities that allows or disallows one to make a film. I'm not quite sure what your question is exactly, could you please elaborate if my below suggestions are off-route?
If it's a question of gaining the
means to create, then it's hardwork and an incredible amount of
networking.
If you're referring to the film having to
belong to a production company, not necessarily. Although it is most rare that this isn't the case, I'm yet to see a law that states that the material
must be owned/created by a production company.
(Festival wise I'm not at all sure, the regulations can change pending on what Festival/Country)
There are certain requirements/legal issues eg Hiring equipment/Public Liability Insurance/Crew/Talent Insurance/Location releases, that more often than not ask for a Production company...
To put it in perspective, in hindsight of what i believe you're asking.
Does a musician have to be under a label to make music?
P.S Welcome, Ash